North Korea now possesses at least six road-mobile intercontinental ballistic missile (ICBM) launchers, but the missiles paired for their use have low reliability, a new report published by the U.S. Department of Defense (DoD) said on Wednesday.

The missile, known as the Hwasong-13 (or KN-08), has a range of more than 3,400 miles (5,471km) and would be capable of hitting much of the continental United States, “if successfully designed and developed”, the report for Congress said.

But the report said the “extremely complex” missile type had yet to be flight-tested, “their current reliability as a weapon system would be low”.